Images & Animations
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Credit
TOPEX/Poseidon, NASA JPL
A giant horseshoe pattern of higher than normal sea-surface heights developing over the last year is beginning to dominate the entire western Pacific and Asiatic oceans, new imagery from the U.S.-French TOPEX/Poseidon satellite shows.
Scientists at NASA's Jet Propulsion Laboratory, Pasadena, Calif., studying the new data believe these abnormally warm ocean temperatures, which contrast with a cool La Niña, may be part of a larger, longer-lasting climate pattern.
The latest data, taken December 30, 1999 through January 8, 2000, show that this slower-developing condition covers most of the Pacific Ocean and has significant implications for global climate change, especially over North America, said Dr. William Patzert, an oceanographer at JPL.
Satellite data from the National Oceanic and Atmospheric Administration clearly illustrate the pattern. Sea-surface temperatures, which directly affect the atmosphere on a daily basis, are available at http://psbsgi1.nesdis.noaa.gov:8080/PSB/EPS/SST/climo.html, and show the same warm and cool water patterns.
The Pacific decadal oscillation waxes and wanes approximately every 20 to 30 years, alternating between its present phase, with a warm horseshoe pattern of higher than normal sea-surface heights connecting the north, west and southern Pacific, in contrast to a cool wedge of lower than normal sea-surface heights in the eastern equatorial Pacific. After that the Pacific switches to the opposite phase, showing a reversal of the warm and cool regions; the horseshoe becomes cool and the wedge warms.
The strength of this climate trend is seen in the current TOPEX/Poseidon satellite image, available at http://www.jpl.nasa.gov/elnino Sea-surface height is shown relative to normal (green) height and reveals cooler water (blue and purple) measuring between 8 and 24 centimeters (3 and 9 inches) lower than normal along the coast of Central and South America, and stretching out into the equatorial Pacific. The giant horseshoe of warmer water (red and white) dominating the western and mid-latitude Pacific has higher than normal sea-surface heights of between 8 and 24 centimeters (3 and 9 inches). For the past year, warmer waters have been expanding slowly and are now beginning to dominate the western and north Pacific.
Although it is too early to definitively label these basin-wide conditions as a strong, multiple-year Pacific decadal oscillation, the current image suggests that simple labels or explanations such as a continuing La Niña/El Niño climate condition could be misleading, Patzert said. In the coming year, scientists using TOPEX/Poseidon data will continue to monitor the development of these conditions and their implications for climate in the next several years.
Metadata
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Sensor
TOPEX/Poseidon -
Visualization Date
2000-01-08
